From c1dc83ae33a76a4dfe19ba159b471c8b1c72671e Mon Sep 17 00:00:00 2001
From: Maurits van Beusekom <maurits@baseflow.com>
Date: Fri, 5 Nov 2021 13:03:40 +0100
Subject: [PATCH 1/5] Implementation of loadFile for WKWebView.

Adds native implementation for the `loadFile` method channel call to the
webview_flutter_wkwebview package.
---
 .../example/ios/RunnerTests/FLTWebViewTests.m | 98 +++++++++++++++++++
 .../example/lib/main.dart                     | 47 +++++++++
 .../example/lib/web_view.dart                 | 14 +++
 .../example/pubspec.yaml                      |  4 +
 .../ios/Classes/FlutterWebView.m              | 41 ++++++++
 5 files changed, 204 insertions(+)

diff --git a/packages/webview_flutter/webview_flutter_wkwebview/example/ios/RunnerTests/FLTWebViewTests.m b/packages/webview_flutter/webview_flutter_wkwebview/example/ios/RunnerTests/FLTWebViewTests.m
index 9d127c2c4aaa..65bf1ee7dc43 100644
--- a/packages/webview_flutter/webview_flutter_wkwebview/example/ios/RunnerTests/FLTWebViewTests.m
+++ b/packages/webview_flutter/webview_flutter_wkwebview/example/ios/RunnerTests/FLTWebViewTests.m
@@ -88,6 +88,104 @@ - (void)testContentInsetsSumAlwaysZeroAfterSetFrame {
   }
 }
 
+- (void)testLoadFileSucceeds {
+  NSString *testFilePath = @"/assets/file.html";
+  NSURL *url = [NSURL fileURLWithPath:testFilePath isDirectory:NO];
+  XCTestExpectation *resultExpectation =
+      [self expectationWithDescription:@"Should return successful result over the method channel."];
+  FLTWebViewController *controller =
+      [[FLTWebViewController alloc] initWithFrame:CGRectMake(0, 0, 300, 400)
+                                   viewIdentifier:1
+                                        arguments:nil
+                                  binaryMessenger:self.mockBinaryMessenger];
+  FLTWKWebView *mockWebView = OCMClassMock(FLTWKWebView.class);
+  controller.webView = mockWebView;
+  [controller onMethodCall:[FlutterMethodCall methodCallWithMethodName:@"loadFile"
+                                                             arguments:testFilePath]
+                    result:^(id _Nullable result) {
+                      XCTAssertNil(result);
+                      [resultExpectation fulfill];
+                    }];
+
+  [self waitForExpectations:@[ resultExpectation ] timeout:30.0];
+  OCMVerify([mockWebView loadFileURL:url
+             allowingReadAccessToURL:[url URLByDeletingLastPathComponent]]);
+}
+
+- (void)testLoadFileFailsWithNilPath {
+  XCTestExpectation *resultExpectation =
+      [self expectationWithDescription:@"Should return failed result over the method channel."];
+  FLTWebViewController *controller =
+      [[FLTWebViewController alloc] initWithFrame:CGRectMake(0, 0, 300, 400)
+                                   viewIdentifier:1
+                                        arguments:nil
+                                  binaryMessenger:self.mockBinaryMessenger];
+  FLTWKWebView *mockWebView = OCMClassMock(FLTWKWebView.class);
+  controller.webView = mockWebView;
+  [controller onMethodCall:[FlutterMethodCall methodCallWithMethodName:@"loadFile" arguments:nil]
+                    result:^(id _Nullable result) {
+                      XCTAssertTrue([result class] == [FlutterError class]);
+                      FlutterError *errorResult = result;
+                      XCTAssertEqualObjects(errorResult.code, @"loadFile_failed");
+                      XCTAssertEqualObjects(errorResult.message, @"Failed parsing file path.");
+                      XCTAssertEqualObjects(errorResult.details, @"Argument is nil.");
+                      [resultExpectation fulfill];
+                    }];
+
+  [self waitForExpectations:@[ resultExpectation ] timeout:1.0];
+  OCMReject([mockWebView loadFileURL:[OCMArg any] allowingReadAccessToURL:[OCMArg any]]);
+}
+
+- (void)testLoadFileFailsWithNonStringPath {
+  XCTestExpectation *resultExpectation =
+      [self expectationWithDescription:@"Should return failed result over the method channel."];
+  FLTWebViewController *controller =
+      [[FLTWebViewController alloc] initWithFrame:CGRectMake(0, 0, 300, 400)
+                                   viewIdentifier:1
+                                        arguments:nil
+                                  binaryMessenger:self.mockBinaryMessenger];
+  FLTWKWebView *mockWebView = OCMClassMock(FLTWKWebView.class);
+  controller.webView = mockWebView;
+  [controller
+      onMethodCall:[FlutterMethodCall methodCallWithMethodName:@"loadFile" arguments:@(10)]
+            result:^(id _Nullable result) {
+              XCTAssertTrue([result class] == [FlutterError class]);
+              FlutterError *errorResult = result;
+              XCTAssertEqualObjects(errorResult.code, @"loadFile_failed");
+              XCTAssertEqualObjects(errorResult.message, @"Failed parsing file path.");
+              XCTAssertEqualObjects(errorResult.details, @"Argument is not of type NSString.");
+              [resultExpectation fulfill];
+            }];
+
+  [self waitForExpectations:@[ resultExpectation ] timeout:1.0];
+  OCMReject([mockWebView loadFileURL:[OCMArg any] allowingReadAccessToURL:[OCMArg any]]);
+}
+
+- (void)testLoadFileFailsWithEmptyPath {
+  XCTestExpectation *resultExpectation =
+      [self expectationWithDescription:@"Should return failed result over the method channel."];
+  FLTWebViewController *controller =
+      [[FLTWebViewController alloc] initWithFrame:CGRectMake(0, 0, 300, 400)
+                                   viewIdentifier:1
+                                        arguments:nil
+                                  binaryMessenger:self.mockBinaryMessenger];
+  FLTWKWebView *mockWebView = OCMClassMock(FLTWKWebView.class);
+  controller.webView = mockWebView;
+  [controller
+      onMethodCall:[FlutterMethodCall methodCallWithMethodName:@"loadFile" arguments:@""]
+            result:^(id _Nullable result) {
+              XCTAssertTrue([result class] == [FlutterError class]);
+              FlutterError *errorResult = result;
+              XCTAssertEqualObjects(errorResult.code, @"loadFile_failed");
+              XCTAssertEqualObjects(errorResult.message, @"Failed parsing file path.");
+              XCTAssertEqualObjects(errorResult.details, @"Argument contains an empty string.");
+              [resultExpectation fulfill];
+            }];
+
+  [self waitForExpectations:@[ resultExpectation ] timeout:1.0];
+  OCMReject([mockWebView loadFileURL:[OCMArg any] allowingReadAccessToURL:[OCMArg any]]);
+}
+
 - (void)testRunJavascriptFailsForNullString {
   // Setup
   FLTWebViewController *controller =
diff --git a/packages/webview_flutter/webview_flutter_wkwebview/example/lib/main.dart b/packages/webview_flutter/webview_flutter_wkwebview/example/lib/main.dart
index 21240f63ec1a..7d85f6441eac 100644
--- a/packages/webview_flutter/webview_flutter_wkwebview/example/lib/main.dart
+++ b/packages/webview_flutter/webview_flutter_wkwebview/example/lib/main.dart
@@ -6,8 +6,11 @@
 
 import 'dart:async';
 import 'dart:convert';
+import 'dart:io';
+
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
+import 'package:path_provider/path_provider.dart';
 import 'package:webview_flutter_platform_interface/webview_flutter_platform_interface.dart';
 
 import 'navigation_decision.dart';
@@ -33,6 +36,21 @@ The navigation delegate is set to block navigation to the youtube website.
 </html>
 ''';
 
+const String kLocalFileExamplePage = '''
+<!DOCTYPE html>
+<html lang="en">
+<head>
+<title>Local demo page</title>
+</head>
+<body>
+
+<h1>Local demo page</h1>
+<p>This is a local page used to demonstrate how to load a local file using the <a href="https://pub.dev/packages/webview_flutter">Flutter webview</a> plugin.</p>
+
+</body>
+</html>
+''';
+
 class _WebViewExample extends StatefulWidget {
   const _WebViewExample({Key? key}) : super(key: key);
 
@@ -120,6 +138,7 @@ enum _MenuOptions {
   listCache,
   clearCache,
   navigationDelegate,
+  loadLocalFile,
 }
 
 class _SampleMenu extends StatelessWidget {
@@ -157,6 +176,9 @@ class _SampleMenu extends StatelessWidget {
               case _MenuOptions.navigationDelegate:
                 _onNavigationDelegateExample(controller.data!, context);
                 break;
+              case _MenuOptions.loadLocalFile:
+                _onLoadLocalFileExample(controller.data!, context);
+                break;
             }
           },
           itemBuilder: (BuildContext context) => <PopupMenuItem<_MenuOptions>>[
@@ -189,6 +211,10 @@ class _SampleMenu extends StatelessWidget {
               value: _MenuOptions.navigationDelegate,
               child: Text('Navigation Delegate example'),
             ),
+            const PopupMenuItem<_MenuOptions>(
+              value: _MenuOptions.loadLocalFile,
+              child: Text('Load local file'),
+            ),
           ],
         );
       },
@@ -259,6 +285,13 @@ class _SampleMenu extends StatelessWidget {
     await controller.loadUrl('data:text/html;base64,$contentBase64');
   }
 
+  void _onLoadLocalFileExample(
+      WebViewController controller, BuildContext context) async {
+    String pathToIndex = await _prepareLocalFile();
+
+    await controller.loadFile(pathToIndex);
+  }
+
   Widget _getCookieList(String cookies) {
     if (cookies == null || cookies == '""') {
       return Container();
@@ -272,6 +305,20 @@ class _SampleMenu extends StatelessWidget {
       children: cookieWidgets.toList(),
     );
   }
+
+  static Future<String> _prepareLocalFile() async {
+    final String tmpDir = (await getTemporaryDirectory()).path;
+    File indexFile = File('$tmpDir/www/index.html');
+
+    if (await indexFile.exists()) {
+      return indexFile.path;
+    }
+
+    await Directory('$tmpDir/www').create(recursive: true);
+    await indexFile.writeAsString(kLocalFileExamplePage);
+
+    return indexFile.path;
+  }
 }
 
 class _NavigationControls extends StatelessWidget {
diff --git a/packages/webview_flutter/webview_flutter_wkwebview/example/lib/web_view.dart b/packages/webview_flutter/webview_flutter_wkwebview/example/lib/web_view.dart
index 403db1f08ac6..671505e2ad2c 100644
--- a/packages/webview_flutter/webview_flutter_wkwebview/example/lib/web_view.dart
+++ b/packages/webview_flutter/webview_flutter_wkwebview/example/lib/web_view.dart
@@ -305,6 +305,20 @@ class WebViewController {
 
   WebView _widget;
 
+  /// Loads the file located on the specified [absoluteFilePath].
+  ///
+  /// The [absoluteFilePath] parameter should contain the absolute path to the
+  /// file as it is stored on the device. For example:
+  /// `/Users/username/Documents/www/index.html`.
+  ///
+  /// Throws an ArgumentError if the [absoluteFilePath] does not exist.
+  Future<void> loadFile(
+    String absoluteFilePath,
+  ) {
+    assert(absoluteFilePath != null || absoluteFilePath.isNotEmpty);
+    return _webViewPlatformController.loadFile(absoluteFilePath);
+  }
+
   /// Loads the specified URL.
   ///
   /// If `headers` is not null and the URL is an HTTP URL, the key value paris in `headers` will
diff --git a/packages/webview_flutter/webview_flutter_wkwebview/example/pubspec.yaml b/packages/webview_flutter/webview_flutter_wkwebview/example/pubspec.yaml
index 229da5e337a5..c8001c8ffde4 100644
--- a/packages/webview_flutter/webview_flutter_wkwebview/example/pubspec.yaml
+++ b/packages/webview_flutter/webview_flutter_wkwebview/example/pubspec.yaml
@@ -8,6 +8,9 @@ environment:
 dependencies:
   flutter:
     sdk: flutter
+
+  path_provider: ^2.0.6
+  
   webview_flutter_wkwebview:
     # When depending on this package from a real application you should use:
     #   webview_flutter: ^x.y.z
@@ -31,3 +34,4 @@ flutter:
   assets:
     - assets/sample_audio.ogg
     - assets/sample_video.mp4
+    
\ No newline at end of file
diff --git a/packages/webview_flutter/webview_flutter_wkwebview/ios/Classes/FlutterWebView.m b/packages/webview_flutter/webview_flutter_wkwebview/ios/Classes/FlutterWebView.m
index 5e12f8acb2ea..3e606575542a 100644
--- a/packages/webview_flutter/webview_flutter_wkwebview/ios/Classes/FlutterWebView.m
+++ b/packages/webview_flutter/webview_flutter_wkwebview/ios/Classes/FlutterWebView.m
@@ -135,6 +135,8 @@ - (UIView*)view {
 - (void)onMethodCall:(FlutterMethodCall*)call result:(FlutterResult)result {
   if ([[call method] isEqualToString:@"updateSettings"]) {
     [self onUpdateSettings:call result:result];
+  } else if ([[call method] isEqualToString:@"loadFile"]) {
+    [self onLoadFile:call result:result];
   } else if ([[call method] isEqualToString:@"loadUrl"]) {
     [self onLoadUrl:call result:result];
   } else if ([[call method] isEqualToString:@"canGoBack"]) {
@@ -185,6 +187,22 @@ - (void)onUpdateSettings:(FlutterMethodCall*)call result:(FlutterResult)result {
   result([FlutterError errorWithCode:@"updateSettings_failed" message:error details:nil]);
 }
 
+- (void)onLoadFile:(FlutterMethodCall*)call result:(FlutterResult)result {
+  NSString* error = nil;
+  if (![FLTWebViewController isValidStringArgument:[call arguments] withErrorMessage:&error]) {
+    result([FlutterError errorWithCode:@"loadFile_failed"
+                               message:@"Failed parsing file path."
+                               details:error]);
+    return;
+  }
+
+  NSURL* url = [NSURL fileURLWithPath:[call arguments] isDirectory:NO];
+  NSURL* baseUrl = [url URLByDeletingLastPathComponent];
+
+  [_webView loadFileURL:url allowingReadAccessToURL:baseUrl];
+  result(nil);
+}
+
 - (void)onLoadUrl:(FlutterMethodCall*)call result:(FlutterResult)result {
   if (![self loadRequest:[call arguments]]) {
     result([FlutterError
@@ -517,6 +535,29 @@ - (void)updateUserAgent:(NSString*)userAgent {
   }
 }
 
++ (bool)isValidStringArgument:(id)argument withErrorMessage:(NSString**)errorDetails {
+  if (!argument) {
+    if (errorDetails) {
+      *errorDetails = @"Argument is nil.";
+    }
+    return NO;
+  }
+  if (![argument isKindOfClass:NSString.class]) {
+    if (errorDetails) {
+      *errorDetails = @"Argument is not of type NSString.";
+    }
+    return NO;
+  }
+  if (![argument length]) {
+    if (errorDetails) {
+      *errorDetails = @"Argument contains an empty string.";
+    }
+    return NO;
+  }
+
+  return YES;
+}
+
 #pragma mark WKUIDelegate
 
 - (WKWebView*)webView:(WKWebView*)webView

From f1343c25576e794e52d31c48fb9df86a3ceda8b8 Mon Sep 17 00:00:00 2001
From: Maurits van Beusekom <maurits@baseflow.com>
Date: Mon, 8 Nov 2021 15:26:31 +0100
Subject: [PATCH 2/5] Implementation of loadHtmlString for WKWebView.

Adds native implementation for the `loadHtmlString` method channel call to the
webview_flutter_wkwebview package.
---
 .../ios/Runner.xcodeproj/project.pbxproj      |   4 +-
 .../xcshareddata/xcschemes/Runner.xcscheme    |   2 +-
 .../example/ios/RunnerTests/FLTWebViewTests.m | 173 ++++++++++++++----
 .../example/lib/main.dart                     |  17 +-
 .../example/lib/web_view.dart                 |  15 ++
 .../ios/Classes/FlutterWebView.m              |  29 +++
 6 files changed, 201 insertions(+), 39 deletions(-)

diff --git a/packages/webview_flutter/webview_flutter_wkwebview/example/ios/Runner.xcodeproj/project.pbxproj b/packages/webview_flutter/webview_flutter_wkwebview/example/ios/Runner.xcodeproj/project.pbxproj
index ba0deb4781d4..c83e0d82e4ec 100644
--- a/packages/webview_flutter/webview_flutter_wkwebview/example/ios/Runner.xcodeproj/project.pbxproj
+++ b/packages/webview_flutter/webview_flutter_wkwebview/example/ios/Runner.xcodeproj/project.pbxproj
@@ -3,7 +3,7 @@
 	archiveVersion = 1;
 	classes = {
 	};
-	objectVersion = 46;
+	objectVersion = 50;
 	objects = {
 
 /* Begin PBXBuildFile section */
@@ -274,7 +274,7 @@
 			isa = PBXProject;
 			attributes = {
 				DefaultBuildSystemTypeForWorkspace = Original;
-				LastUpgradeCheck = 1030;
+				LastUpgradeCheck = 1300;
 				ORGANIZATIONNAME = "The Flutter Authors";
 				TargetAttributes = {
 					68BDCAE823C3F7CB00D9C032 = {
diff --git a/packages/webview_flutter/webview_flutter_wkwebview/example/ios/Runner.xcodeproj/xcshareddata/xcschemes/Runner.xcscheme b/packages/webview_flutter/webview_flutter_wkwebview/example/ios/Runner.xcodeproj/xcshareddata/xcschemes/Runner.xcscheme
index d7453a8ce862..cb713d767632 100644
--- a/packages/webview_flutter/webview_flutter_wkwebview/example/ios/Runner.xcodeproj/xcshareddata/xcschemes/Runner.xcscheme
+++ b/packages/webview_flutter/webview_flutter_wkwebview/example/ios/Runner.xcodeproj/xcshareddata/xcschemes/Runner.xcscheme
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "1030"
+   LastUpgradeVersion = "1300"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"
diff --git a/packages/webview_flutter/webview_flutter_wkwebview/example/ios/RunnerTests/FLTWebViewTests.m b/packages/webview_flutter/webview_flutter_wkwebview/example/ios/RunnerTests/FLTWebViewTests.m
index 65bf1ee7dc43..adbb1453021a 100644
--- a/packages/webview_flutter/webview_flutter_wkwebview/example/ios/RunnerTests/FLTWebViewTests.m
+++ b/packages/webview_flutter/webview_flutter_wkwebview/example/ios/RunnerTests/FLTWebViewTests.m
@@ -112,9 +112,15 @@ - (void)testLoadFileSucceeds {
              allowingReadAccessToURL:[url URLByDeletingLastPathComponent]]);
 }
 
-- (void)testLoadFileFailsWithNilPath {
-  XCTestExpectation *resultExpectation =
-      [self expectationWithDescription:@"Should return failed result over the method channel."];
+- (void)testLoadFileFailsWithInvalidPath {
+  NSArray *resultExpectations = @[
+    [self expectationWithDescription:@"Should return failed result when argument is nil."],
+    [self expectationWithDescription:
+              @"Should return failed result when argument is not of type NSString*."],
+    [self expectationWithDescription:
+              @"Should return failed result when argument is an empty string."],
+  ];
+
   FLTWebViewController *controller =
       [[FLTWebViewController alloc] initWithFrame:CGRectMake(0, 0, 300, 400)
                                    viewIdentifier:1
@@ -124,21 +130,40 @@ - (void)testLoadFileFailsWithNilPath {
   controller.webView = mockWebView;
   [controller onMethodCall:[FlutterMethodCall methodCallWithMethodName:@"loadFile" arguments:nil]
                     result:^(id _Nullable result) {
-                      XCTAssertTrue([result class] == [FlutterError class]);
-                      FlutterError *errorResult = result;
-                      XCTAssertEqualObjects(errorResult.code, @"loadFile_failed");
-                      XCTAssertEqualObjects(errorResult.message, @"Failed parsing file path.");
-                      XCTAssertEqualObjects(errorResult.details, @"Argument is nil.");
-                      [resultExpectation fulfill];
+                      FlutterError *expected =
+                          [FlutterError errorWithCode:@"loadFile_failed"
+                                              message:@"Failed parsing file path."
+                                              details:@"Argument is nil."];
+                      [FLTWebViewTests assertFlutterError:result withExpected:expected];
+                      [resultExpectations[0] fulfill];
+                    }];
+  [controller onMethodCall:[FlutterMethodCall methodCallWithMethodName:@"loadFile" arguments:@(10)]
+                    result:^(id _Nullable result) {
+                      FlutterError *expected =
+                          [FlutterError errorWithCode:@"loadFile_failed"
+                                              message:@"Failed parsing file path."
+                                              details:@"Argument is not of type NSString."];
+                      [FLTWebViewTests assertFlutterError:result withExpected:expected];
+                      [resultExpectations[1] fulfill];
+                    }];
+  [controller onMethodCall:[FlutterMethodCall methodCallWithMethodName:@"loadFile" arguments:@""]
+                    result:^(id _Nullable result) {
+                      FlutterError *expected =
+                          [FlutterError errorWithCode:@"loadFile_failed"
+                                              message:@"Failed parsing file path."
+                                              details:@"Argument contains an empty string."];
+                      [FLTWebViewTests assertFlutterError:result withExpected:expected];
+                      [resultExpectations[2] fulfill];
                     }];
 
-  [self waitForExpectations:@[ resultExpectation ] timeout:1.0];
+  [self waitForExpectations:resultExpectations timeout:1.0];
   OCMReject([mockWebView loadFileURL:[OCMArg any] allowingReadAccessToURL:[OCMArg any]]);
 }
 
-- (void)testLoadFileFailsWithNonStringPath {
+- (void)testLoadFileSucceedsWithBaseUrl {
+  NSURL *baseUrl = [NSURL URLWithString:@"https://flutter.dev"];
   XCTestExpectation *resultExpectation =
-      [self expectationWithDescription:@"Should return failed result over the method channel."];
+      [self expectationWithDescription:@"Should return successful result over the method channel."];
   FLTWebViewController *controller =
       [[FLTWebViewController alloc] initWithFrame:CGRectMake(0, 0, 300, 400)
                                    viewIdentifier:1
@@ -146,24 +171,23 @@ - (void)testLoadFileFailsWithNonStringPath {
                                   binaryMessenger:self.mockBinaryMessenger];
   FLTWKWebView *mockWebView = OCMClassMock(FLTWKWebView.class);
   controller.webView = mockWebView;
-  [controller
-      onMethodCall:[FlutterMethodCall methodCallWithMethodName:@"loadFile" arguments:@(10)]
-            result:^(id _Nullable result) {
-              XCTAssertTrue([result class] == [FlutterError class]);
-              FlutterError *errorResult = result;
-              XCTAssertEqualObjects(errorResult.code, @"loadFile_failed");
-              XCTAssertEqualObjects(errorResult.message, @"Failed parsing file path.");
-              XCTAssertEqualObjects(errorResult.details, @"Argument is not of type NSString.");
-              [resultExpectation fulfill];
-            }];
+  [controller onMethodCall:[FlutterMethodCall methodCallWithMethodName:@"loadHtmlString"
+                                                             arguments:@{
+                                                               @"html" : @"some HTML string",
+                                                               @"baseUrl" : @"https://flutter.dev"
+                                                             }]
+                    result:^(id _Nullable result) {
+                      XCTAssertNil(result);
+                      [resultExpectation fulfill];
+                    }];
 
-  [self waitForExpectations:@[ resultExpectation ] timeout:1.0];
-  OCMReject([mockWebView loadFileURL:[OCMArg any] allowingReadAccessToURL:[OCMArg any]]);
+  [self waitForExpectations:@[ resultExpectation ] timeout:30.0];
+  OCMVerify([mockWebView loadHTMLString:@"some HTML string" baseURL:baseUrl]);
 }
 
-- (void)testLoadFileFailsWithEmptyPath {
+- (void)testLoadFileSucceedsWithoutBaseUrl {
   XCTestExpectation *resultExpectation =
-      [self expectationWithDescription:@"Should return failed result over the method channel."];
+      [self expectationWithDescription:@"Should return successful result over the method channel."];
   FLTWebViewController *controller =
       [[FLTWebViewController alloc] initWithFrame:CGRectMake(0, 0, 300, 400)
                                    viewIdentifier:1
@@ -172,18 +196,91 @@ - (void)testLoadFileFailsWithEmptyPath {
   FLTWKWebView *mockWebView = OCMClassMock(FLTWKWebView.class);
   controller.webView = mockWebView;
   [controller
-      onMethodCall:[FlutterMethodCall methodCallWithMethodName:@"loadFile" arguments:@""]
+      onMethodCall:[FlutterMethodCall methodCallWithMethodName:@"loadHtmlString"
+                                                     arguments:@{@"html" : @"some HTML string"}]
             result:^(id _Nullable result) {
-              XCTAssertTrue([result class] == [FlutterError class]);
-              FlutterError *errorResult = result;
-              XCTAssertEqualObjects(errorResult.code, @"loadFile_failed");
-              XCTAssertEqualObjects(errorResult.message, @"Failed parsing file path.");
-              XCTAssertEqualObjects(errorResult.details, @"Argument contains an empty string.");
+              XCTAssertNil(result);
               [resultExpectation fulfill];
             }];
 
-  [self waitForExpectations:@[ resultExpectation ] timeout:1.0];
-  OCMReject([mockWebView loadFileURL:[OCMArg any] allowingReadAccessToURL:[OCMArg any]]);
+  [self waitForExpectations:@[ resultExpectation ] timeout:30.0];
+  OCMVerify([mockWebView loadHTMLString:@"some HTML string" baseURL:nil]);
+}
+
+- (void)testLoadHtmlStringFailsWithInvalidArgument {
+  NSArray *resultExpectations = @[
+    [self expectationWithDescription:@"Should return failed result when argument is nil."],
+    [self expectationWithDescription:
+              @"Should return failed result when argument is not of type NSDictionary*."],
+    [self expectationWithDescription:@"Should return failed result when HTML argument is nil."],
+    [self expectationWithDescription:
+              @"Should return failed result when HTML argument is not of type NSString*."],
+    [self expectationWithDescription:
+              @"Should return failed result when HTML argument is an empty string."],
+  ];
+
+  FLTWebViewController *controller =
+      [[FLTWebViewController alloc] initWithFrame:CGRectMake(0, 0, 300, 400)
+                                   viewIdentifier:1
+                                        arguments:nil
+                                  binaryMessenger:self.mockBinaryMessenger];
+  FLTWKWebView *mockWebView = OCMClassMock(FLTWKWebView.class);
+  controller.webView = mockWebView;
+  FlutterError *expected = [FlutterError
+      errorWithCode:@"loadHtmlString_failed"
+            message:@"Failed parsing arguments."
+            details:@"Arguments should be a dictionary containing at least a 'html' element and "
+                    @"optionally a 'baseUrl' argument. For example: `@{ @\"html\": @\"some html "
+                    @"code\", @\"baseUrl\": @\"https://flutter.dev\" }`"];
+  [controller onMethodCall:[FlutterMethodCall methodCallWithMethodName:@"loadHtmlString"
+                                                             arguments:nil]
+                    result:^(id _Nullable result) {
+                      [FLTWebViewTests assertFlutterError:result withExpected:expected];
+                      [resultExpectations[0] fulfill];
+                    }];
+  [controller onMethodCall:[FlutterMethodCall methodCallWithMethodName:@"loadHtmlString"
+                                                             arguments:@""]
+                    result:^(id _Nullable result) {
+                      [FLTWebViewTests assertFlutterError:result withExpected:expected];
+                      [resultExpectations[1] fulfill];
+                    }];
+  [controller onMethodCall:[FlutterMethodCall methodCallWithMethodName:@"loadHtmlString"
+                                                             arguments:@{}]
+                    result:^(id _Nullable result) {
+                      FlutterError *expected =
+                          [FlutterError errorWithCode:@"loadHtmlString_failed"
+                                              message:@"Failed parsing HTML string argument."
+                                              details:@"Argument is nil."];
+                      [FLTWebViewTests assertFlutterError:result withExpected:expected];
+                      [resultExpectations[2] fulfill];
+                    }];
+  [controller onMethodCall:[FlutterMethodCall methodCallWithMethodName:@"loadHtmlString"
+                                                             arguments:@{
+                                                               @"html" : @(42),
+                                                             }]
+                    result:^(id _Nullable result) {
+                      FlutterError *expected =
+                          [FlutterError errorWithCode:@"loadHtmlString_failed"
+                                              message:@"Failed parsing HTML string argument."
+                                              details:@"Argument is not of type NSString."];
+                      [FLTWebViewTests assertFlutterError:result withExpected:expected];
+                      [resultExpectations[3] fulfill];
+                    }];
+  [controller onMethodCall:[FlutterMethodCall methodCallWithMethodName:@"loadHtmlString"
+                                                             arguments:@{
+                                                               @"html" : @"",
+                                                             }]
+                    result:^(id _Nullable result) {
+                      FlutterError *expected =
+                          [FlutterError errorWithCode:@"loadHtmlString_failed"
+                                              message:@"Failed parsing HTML string argument."
+                                              details:@"Argument contains an empty string."];
+                      [FLTWebViewTests assertFlutterError:result withExpected:expected];
+                      [resultExpectations[4] fulfill];
+                    }];
+
+  [self waitForExpectations:resultExpectations timeout:1.0];
+  OCMReject([mockWebView loadHTMLString:[OCMArg any] baseURL:[OCMArg any]]);
 }
 
 - (void)testRunJavascriptFailsForNullString {
@@ -399,4 +496,12 @@ - (void)testRunJavascriptReturningResultReturnsErrorResultForWKError {
   [self waitForExpectationsWithTimeout:30.0 handler:nil];
 }
 
++ (void)assertFlutterError:(id)actual withExpected:(FlutterError *)expected {
+  XCTAssertTrue([actual class] == [FlutterError class]);
+  FlutterError *errorResult = actual;
+  XCTAssertEqualObjects(errorResult.code, expected.code);
+  XCTAssertEqualObjects(errorResult.message, expected.message);
+  XCTAssertEqualObjects(errorResult.details, expected.details);
+}
+
 @end
diff --git a/packages/webview_flutter/webview_flutter_wkwebview/example/lib/main.dart b/packages/webview_flutter/webview_flutter_wkwebview/example/lib/main.dart
index 7d85f6441eac..f7f2f8b5c7bc 100644
--- a/packages/webview_flutter/webview_flutter_wkwebview/example/lib/main.dart
+++ b/packages/webview_flutter/webview_flutter_wkwebview/example/lib/main.dart
@@ -40,12 +40,12 @@ const String kLocalFileExamplePage = '''
 <!DOCTYPE html>
 <html lang="en">
 <head>
-<title>Local demo page</title>
+<title>Load file or HTML string example</title>
 </head>
 <body>
 
 <h1>Local demo page</h1>
-<p>This is a local page used to demonstrate how to load a local file using the <a href="https://pub.dev/packages/webview_flutter">Flutter webview</a> plugin.</p>
+<p>This is an example page used to demonstrate how to load a local file or HTML string using the <a href="https://pub.dev/packages/webview_flutter">Flutter webview</a> plugin.</p>
 
 </body>
 </html>
@@ -139,6 +139,7 @@ enum _MenuOptions {
   clearCache,
   navigationDelegate,
   loadLocalFile,
+  loadHtmlString,
 }
 
 class _SampleMenu extends StatelessWidget {
@@ -179,6 +180,9 @@ class _SampleMenu extends StatelessWidget {
               case _MenuOptions.loadLocalFile:
                 _onLoadLocalFileExample(controller.data!, context);
                 break;
+              case _MenuOptions.loadHtmlString:
+                _onLoadHtmlStringExample(controller.data!, context);
+                break;
             }
           },
           itemBuilder: (BuildContext context) => <PopupMenuItem<_MenuOptions>>[
@@ -211,6 +215,10 @@ class _SampleMenu extends StatelessWidget {
               value: _MenuOptions.navigationDelegate,
               child: Text('Navigation Delegate example'),
             ),
+            const PopupMenuItem<_MenuOptions>(
+              value: _MenuOptions.loadHtmlString,
+              child: Text('Load HTML string'),
+            ),
             const PopupMenuItem<_MenuOptions>(
               value: _MenuOptions.loadLocalFile,
               child: Text('Load local file'),
@@ -292,6 +300,11 @@ class _SampleMenu extends StatelessWidget {
     await controller.loadFile(pathToIndex);
   }
 
+  void _onLoadHtmlStringExample(
+      WebViewController controller, BuildContext context) async {
+    await controller.loadHtmlString(kLocalFileExamplePage);
+  }
+
   Widget _getCookieList(String cookies) {
     if (cookies == null || cookies == '""') {
       return Container();
diff --git a/packages/webview_flutter/webview_flutter_wkwebview/example/lib/web_view.dart b/packages/webview_flutter/webview_flutter_wkwebview/example/lib/web_view.dart
index 671505e2ad2c..ca4359825a67 100644
--- a/packages/webview_flutter/webview_flutter_wkwebview/example/lib/web_view.dart
+++ b/packages/webview_flutter/webview_flutter_wkwebview/example/lib/web_view.dart
@@ -319,6 +319,21 @@ class WebViewController {
     return _webViewPlatformController.loadFile(absoluteFilePath);
   }
 
+  /// Loads the supplied HTML string.
+  ///
+  /// The [baseUrl] parameter is used when resolving relative URLs within the
+  /// HTML string.
+  Future<void> loadHtmlString(
+    String html, {
+    String? baseUrl,
+  }) {
+    assert(html != null || html.isNotEmpty);
+    return _webViewPlatformController.loadHtmlString(
+      html,
+      baseUrl: baseUrl,
+    );
+  }
+
   /// Loads the specified URL.
   ///
   /// If `headers` is not null and the URL is an HTTP URL, the key value paris in `headers` will
diff --git a/packages/webview_flutter/webview_flutter_wkwebview/ios/Classes/FlutterWebView.m b/packages/webview_flutter/webview_flutter_wkwebview/ios/Classes/FlutterWebView.m
index 3e606575542a..58fe64a41da2 100644
--- a/packages/webview_flutter/webview_flutter_wkwebview/ios/Classes/FlutterWebView.m
+++ b/packages/webview_flutter/webview_flutter_wkwebview/ios/Classes/FlutterWebView.m
@@ -137,6 +137,8 @@ - (void)onMethodCall:(FlutterMethodCall*)call result:(FlutterResult)result {
     [self onUpdateSettings:call result:result];
   } else if ([[call method] isEqualToString:@"loadFile"]) {
     [self onLoadFile:call result:result];
+  } else if ([[call method] isEqualToString:@"loadHtmlString"]) {
+    [self onLoadHtmlString:call result:result];
   } else if ([[call method] isEqualToString:@"loadUrl"]) {
     [self onLoadUrl:call result:result];
   } else if ([[call method] isEqualToString:@"canGoBack"]) {
@@ -203,6 +205,33 @@ - (void)onLoadFile:(FlutterMethodCall*)call result:(FlutterResult)result {
   result(nil);
 }
 
+- (void)onLoadHtmlString:(FlutterMethodCall*)call result:(FlutterResult)result {
+  NSDictionary* arguments = [call arguments];
+  if (!arguments || ![arguments isKindOfClass:NSDictionary.class]) {
+    result([FlutterError
+        errorWithCode:@"loadHtmlString_failed"
+              message:@"Failed parsing arguments."
+              details:@"Arguments should be a dictionary containing at least a 'html' element and "
+                      @"optionally a 'baseUrl' argument. For example: `@{ @\"html\": @\"some html "
+                      @"code\", @\"baseUrl\": @\"https://flutter.dev\" }`"]);
+    return;
+  }
+
+  NSString* htmlString = [call arguments][@"html"];
+  NSString* baseUrl =
+      [call arguments][@"baseUrl"] == [NSNull null] ? nil : [call arguments][@"baseUrl"];
+  NSString* error = nil;
+  if (![FLTWebViewController isValidStringArgument:htmlString withErrorMessage:&error]) {
+    result([FlutterError errorWithCode:@"loadHtmlString_failed"
+                               message:@"Failed parsing HTML string argument."
+                               details:error]);
+    return;
+  }
+
+  [_webView loadHTMLString:htmlString baseURL:[NSURL URLWithString:baseUrl]];
+  result(nil);
+}
+
 - (void)onLoadUrl:(FlutterMethodCall*)call result:(FlutterResult)result {
   if (![self loadRequest:[call arguments]]) {
     result([FlutterError

From b94583921cebef47b88fcf27d8fa649234098bee Mon Sep 17 00:00:00 2001
From: Maurits van Beusekom <maurits@baseflow.com>
Date: Tue, 9 Nov 2021 09:35:13 +0100
Subject: [PATCH 3/5] Bump version number

---
 .../webview_flutter/webview_flutter_wkwebview/CHANGELOG.md    | 4 ++++
 .../webview_flutter/webview_flutter_wkwebview/pubspec.yaml    | 2 +-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/packages/webview_flutter/webview_flutter_wkwebview/CHANGELOG.md b/packages/webview_flutter/webview_flutter_wkwebview/CHANGELOG.md
index 4db6dbfd2864..28c9c1ed3522 100644
--- a/packages/webview_flutter/webview_flutter_wkwebview/CHANGELOG.md
+++ b/packages/webview_flutter/webview_flutter_wkwebview/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 2.3.0
+
+* Implemented new `loadFile` and `loadHtmlString` methods from the platform interface.
+
 ## 2.2.0
 
 * Implemented new `runJavascript` and `runJavascriptReturningResult` methods in platform interface.
diff --git a/packages/webview_flutter/webview_flutter_wkwebview/pubspec.yaml b/packages/webview_flutter/webview_flutter_wkwebview/pubspec.yaml
index 5176adb9749c..ec5bd271cfa5 100644
--- a/packages/webview_flutter/webview_flutter_wkwebview/pubspec.yaml
+++ b/packages/webview_flutter/webview_flutter_wkwebview/pubspec.yaml
@@ -2,7 +2,7 @@ name: webview_flutter_wkwebview
 description: A Flutter plugin that provides a WebView widget based on Apple's WKWebView control.
 repository: https://github.com/flutter/plugins/tree/master/packages/webview_flutter/webview_flutter_wkwebview
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+webview%22
-version: 2.2.0
+version: 2.3.0
 
 environment:
   sdk: ">=2.14.0 <3.0.0"

From d5cf9f9887c9a6ef5cff22e58f4326f133d9524f Mon Sep 17 00:00:00 2001
From: Maurits van Beusekom <maurits@baseflow.com>
Date: Thu, 11 Nov 2021 17:02:46 +0100
Subject: [PATCH 4/5] Apply feedback on PR

---
 .../example/lib/main.dart                     | 10 ++++-----
 .../example/lib/web_view.dart                 |  2 --
 .../ios/Classes/FlutterWebView.m              | 21 ++++++++++++++++++-
 3 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/packages/webview_flutter/webview_flutter_wkwebview/example/lib/main.dart b/packages/webview_flutter/webview_flutter_wkwebview/example/lib/main.dart
index 2efdf31a24af..72168ecc8568 100644
--- a/packages/webview_flutter/webview_flutter_wkwebview/example/lib/main.dart
+++ b/packages/webview_flutter/webview_flutter_wkwebview/example/lib/main.dart
@@ -46,7 +46,11 @@ const String kLocalFileExamplePage = '''
 <body>
 
 <h1>Local demo page</h1>
-<p>This is an example page used to demonstrate how to load a local file or HTML string using the <a href="https://pub.dev/packages/webview_flutter">Flutter webview</a> plugin.</p>
+<p>
+  This is an example page used to demonstrate how to load a local file or HTML 
+  string using the <a href="https://pub.dev/packages/webview_flutter">Flutter 
+  webview</a> plugin.
+</p>
 
 </body>
 </html>
@@ -343,10 +347,6 @@ class _SampleMenu extends StatelessWidget {
     final String tmpDir = (await getTemporaryDirectory()).path;
     File indexFile = File('$tmpDir/www/index.html');
 
-    if (await indexFile.exists()) {
-      return indexFile.path;
-    }
-
     await Directory('$tmpDir/www').create(recursive: true);
     await indexFile.writeAsString(kLocalFileExamplePage);
 
diff --git a/packages/webview_flutter/webview_flutter_wkwebview/example/lib/web_view.dart b/packages/webview_flutter/webview_flutter_wkwebview/example/lib/web_view.dart
index f3a84c01ab7f..ddc475342b04 100644
--- a/packages/webview_flutter/webview_flutter_wkwebview/example/lib/web_view.dart
+++ b/packages/webview_flutter/webview_flutter_wkwebview/example/lib/web_view.dart
@@ -315,7 +315,6 @@ class WebViewController {
   Future<void> loadFile(
     String absoluteFilePath,
   ) {
-    assert(absoluteFilePath != null || absoluteFilePath.isNotEmpty);
     return _webViewPlatformController.loadFile(absoluteFilePath);
   }
 
@@ -327,7 +326,6 @@ class WebViewController {
     String html, {
     String? baseUrl,
   }) {
-    assert(html != null || html.isNotEmpty);
     return _webViewPlatformController.loadHtmlString(
       html,
       baseUrl: baseUrl,
diff --git a/packages/webview_flutter/webview_flutter_wkwebview/ios/Classes/FlutterWebView.m b/packages/webview_flutter/webview_flutter_wkwebview/ios/Classes/FlutterWebView.m
index 390e5f368467..5ef8e847ca65 100644
--- a/packages/webview_flutter/webview_flutter_wkwebview/ios/Classes/FlutterWebView.m
+++ b/packages/webview_flutter/webview_flutter_wkwebview/ios/Classes/FlutterWebView.m
@@ -206,6 +206,17 @@ - (void)onLoadFile:(FlutterMethodCall*)call result:(FlutterResult)result {
   }
 
   NSURL* url = [NSURL fileURLWithPath:[call arguments] isDirectory:NO];
+
+  if (!url) {
+    NSString* errorDetails = [NSString stringWithFormat:@"Initializing NSURL with the supplied "
+                                                        @"'%@' path resulted in a nil value.",
+                                                        [call arguments]];
+    result([FlutterError errorWithCode:@"loadFile_failed"
+                               message:@"Failed parsing file path."
+                               details:errorDetails]);
+    return;
+  }
+
   NSURL* baseUrl = [url URLByDeletingLastPathComponent];
 
   [_webView loadFileURL:url allowingReadAccessToURL:baseUrl];
@@ -214,7 +225,7 @@ - (void)onLoadFile:(FlutterMethodCall*)call result:(FlutterResult)result {
 
 - (void)onLoadHtmlString:(FlutterMethodCall*)call result:(FlutterResult)result {
   NSDictionary* arguments = [call arguments];
-  if (!arguments || ![arguments isKindOfClass:NSDictionary.class]) {
+  if (![arguments isKindOfClass:NSDictionary.class]) {
     result([FlutterError
         errorWithCode:@"loadHtmlString_failed"
               message:@"Failed parsing arguments."
@@ -603,6 +614,14 @@ - (void)updateUserAgent:(NSString*)userAgent {
   }
 }
 
+/**
+ * Validates if the given `argument` is a non-null non-empty string.
+ *
+ * @param argument The argument that should be validated.
+ * @param errorDetails An optional NSString variable which will contain a detailed error message in
+ * case the supplied argument is not valid.
+ * @return `true` if the given `argument` is a valid non-null, non-empty string; otherwise `false`.
+ */
 + (bool)isValidStringArgument:(id)argument withErrorMessage:(NSString**)errorDetails {
   if (!argument) {
     if (errorDetails) {

From 98eb2368af9dcee3912e39116ecd43a1ad7d92a4 Mon Sep 17 00:00:00 2001
From: Maurits van Beusekom <maurits@baseflow.com>
Date: Fri, 12 Nov 2021 08:53:04 +0100
Subject: [PATCH 5/5] Fix final nits

---
 .../webview_flutter_wkwebview/example/lib/web_view.dart     | 2 ++
 .../webview_flutter_wkwebview/ios/Classes/FlutterWebView.m  | 6 +++---
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/packages/webview_flutter/webview_flutter_wkwebview/example/lib/web_view.dart b/packages/webview_flutter/webview_flutter_wkwebview/example/lib/web_view.dart
index ddc475342b04..ab4b77336765 100644
--- a/packages/webview_flutter/webview_flutter_wkwebview/example/lib/web_view.dart
+++ b/packages/webview_flutter/webview_flutter_wkwebview/example/lib/web_view.dart
@@ -315,6 +315,7 @@ class WebViewController {
   Future<void> loadFile(
     String absoluteFilePath,
   ) {
+    assert(absoluteFilePath.isNotEmpty);
     return _webViewPlatformController.loadFile(absoluteFilePath);
   }
 
@@ -326,6 +327,7 @@ class WebViewController {
     String html, {
     String? baseUrl,
   }) {
+    assert(html.isNotEmpty);
     return _webViewPlatformController.loadHtmlString(
       html,
       baseUrl: baseUrl,
diff --git a/packages/webview_flutter/webview_flutter_wkwebview/ios/Classes/FlutterWebView.m b/packages/webview_flutter/webview_flutter_wkwebview/ios/Classes/FlutterWebView.m
index 5ef8e847ca65..351d1ae58760 100644
--- a/packages/webview_flutter/webview_flutter_wkwebview/ios/Classes/FlutterWebView.m
+++ b/packages/webview_flutter/webview_flutter_wkwebview/ios/Classes/FlutterWebView.m
@@ -615,14 +615,14 @@ - (void)updateUserAgent:(NSString*)userAgent {
 }
 
 /**
- * Validates if the given `argument` is a non-null non-empty string.
+ * Validates if the given `argument` is a non-null, non-empty string.
  *
  * @param argument The argument that should be validated.
  * @param errorDetails An optional NSString variable which will contain a detailed error message in
  * case the supplied argument is not valid.
- * @return `true` if the given `argument` is a valid non-null, non-empty string; otherwise `false`.
+ * @return `YES` if the given `argument` is a valid non-null, non-empty string; otherwise `NO`.
  */
-+ (bool)isValidStringArgument:(id)argument withErrorMessage:(NSString**)errorDetails {
++ (BOOL)isValidStringArgument:(id)argument withErrorMessage:(NSString**)errorDetails {
   if (!argument) {
     if (errorDetails) {
       *errorDetails = @"Argument is nil.";